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Time Sensitive: Rule change to match Lemons cage minimum wall thickness?


w0t
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I noticed that Lemons moved to a 1.5" x 0.120" minimum roll cage tube dimension for light cars at some point. What are the chances ChampCar will move in that direction soon? 

 

I'm extremely curious as I'm looking at a Miata with a 1.5" x 0.095" Spec Miata-style cage currently installed by a race shop in the Pacific Northwest. I'm trying to avoid throwing money down a hole and having to replace the cage in a year or two.

 

Any thoughts? I have to make a purchase commitment by tomorrow afternoon or lose the car to the next buyer in line.

Edited by w0t
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Yes, DOM tubing recommended over ERW, but tube dimensions are fixed:

 

https://24hoursoflemons.com/prices-rules/

3.E.1.a Rollbar Tubing and Spreader-Plate Specs. Minimum tubing size for cars weighing under 3000 pounds as raced is 1.50″ x .120″ or 1.75″ x .095″. Cars weighing over 3000 pounds as raced must use a minimum tubing size of 1.75″ x.120″. Properly bent, racecar-grade and -quality tubing is mandatory: no stretched or crushed bends allowed. DOM mild steel is very strongly recommended over ERW (seamed) tubing.  All spreader plates must be mild steel, at least 24 square inches, and at least .125” thick.

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4 hours ago, FlorahDorah said:

Pretty sure you can 'make' a Miata under 3000 lbs..... 

I am not understanding this comment....

 

Help me out.

 

The OP was asking if the tubing thickness for a lightweight Champcar will change from an allowable of 1.5 x .095" to 1.5 x .120".

 

 

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20 minutes ago, wvumtnbkr said:

I am not understanding this comment....

 

Help me out.

 

The OP was asking if the tubing thickness for a lightweight Champcar will change from an allowable of 1.5 x .095" to 1.5 x .120".

 

 

 

Not exactly. He asked what are the chances of ChampCar going to 1.5 x .120". I don't think anyone knows the answer to that question, right? So I assumed he looked it up and we're not there yet (our rules provided below so I'm not talking out of my butt now). Even Lemons hasn't gone there fully as he will be okay if he buys this car with 0.095" AND makes sure it is less than 3000 lbs.

 

For us it is a little different: 

 

3.2.14.1. Minimum tubing size for cars weighing UNDER 2,500 pounds must use a minimum tubing size of 1.50” x .095. 

3.2.14.2. Minimum tubing size for cars weighing OVER 2,500 pounds must use a minimum tubing size of 1.75” x .095 or 1.50” x .120”. 

 

So it looks like his Miata needs to weigh less than 2500 lbs. Again, no problem for a Miata. He can buy the car and take weight out of it if he needs to. Which would make the car faster in any case. I think it's a win for the OP. 

Edited by FlorahDorah
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6 hours ago, jmabarone said:

Lemons rule doesn't specify DOM tubing but recommends it.  Why not ask Lemons to see if that cage would be legal?

 

I don't see why we would need to change a rule that would make a ton of cars in this series unable to pass tech.  

 

I'm not really that concerned if Lemons likes the cage or not as I'm not that interested in running in their "50% full course yellow flag parade" series. The question was really whether other low cost series like ChampCar were also planning a move in in the direction of requiring sturdier cage tube construction, which would make my impending purchase (even more) financially dubious.

 

Suze Orman would definitely not approve :)

Edited by w0t
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8 minutes ago, w0t said:

 

I'm not really that concerned if Lemons likes the cage or not as I'm not that interested in running in their "50% full course yellow flag parade" series. The question was really whether other low cost series like ChampCar were also planning a move in in the direction of requiring sturdier cage tube construction, which would make my impending purchase (even more) financially dubious.

 

Suze Orman would definitely not approve :)

 

I would not be overly concerned. I just put a .095 x 1.5" cage in a chumpcar a few weeks ago. 

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3 hours ago, FlorahDorah said:

 

Not exactly. He asked what are the chances of ChampCar going to 1.5 x .120". I don't think anyone knows the answer to that question, right? So I assumed he looked it up and we're not there yet (our rules provided below so I'm not talking out of my butt now). Even Lemons hasn't gone there fully as he will be okay if he buys this car with 0.095" AND makes sure it is less than 3000 lbs.

 

For us it is a little different: 

 

3.2.14.1. Minimum tubing size for cars weighing UNDER 2,500 pounds must use a minimum tubing size of 1.50” x .095. 

3.2.14.2. Minimum tubing size for cars weighing OVER 2,500 pounds must use a minimum tubing size of 1.75” x .095 or 1.50” x .120”. 

 

So it looks like his Miata needs to weigh less than 2500 lbs. Again, no problem for a Miata. He can buy the car and take weight out of it if he needs to. Which would make the car faster in any case. I think it's a win for the OP. 

Gotcha!

 

Sorry if my initial response sounded rude.  I hadn't meant it that way.  I was seriously confused.

 

Now, I am less confused.

 

Thanks!

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10 minutes ago, wvumtnbkr said:

Gotcha!

 

Sorry if my initial response sounded rude.  I hadn't meant it that way.  I was seriously confused.

 

Now, I am less confused.

 

Thanks!

 

No worries. I just jumped to the end, looping out all that other stuff. You are keeping me honest.

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In the North East, I have gone through Chump Champ tech and Lemon tech with the Beetle and I will say Lemons Jeff is all over the cage he does car builds and a lot of cage builds too.

I am doing a cage right now and I have both books printed and open on the table. I am using 1.75 .095 DOM  and I may hit below 2500 LB.

If you are going to build for both here is what I did.

  • The tallest drive must have 2 inches from top of the main hoop and side roof bars to helmet ( not Chumps half the bar!!) Don't bring him when going through tech
  • the  gap between top and bottom sidebars use the min 7.5 in or 8 in to be safe
  • the rear bars fight for the 45deg placement and run them as high as you can on the main hoop bends 
  •  show your best welds

Bob Mann

www.DRVOLKS.com

bobtec@comcast.net

drvolkslogo.jpg   

Edited by DRVOLKS
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I'm not sure If your figures are correct. I don't think they agree with these charts from Ryerson Metals. 

 

 

image.jpeg

Edited by mcoppola
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17 minutes ago, mcoppola said:

I'm not sure where you got your figures from, but they don't agree with these charts from Alro Metals. 

 

 

What are the weights for 1.75"X0.95, 1.5"X0.120, 1.75"X0.120?  Is the 60' a reasonable estimate for a cage?  Just curious how much extra weight we put in our cage.

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14 minutes ago, mcoppola said:

I couldn't attach this chart to my previous post, but here are the weights for 1.75" DOM.

Yes, 60' is about average for a cage.

 

 

Thanks, only 25 extra pounds for our 1.75X0.120 versus the lightest we could have gone, I'm good with that.

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